Helianthus annuus (Common Sunflower)
Asteraceae (Sunflower Family)

Semi-desert, foothills, montane. Disturbed areas, openings. Summer, fall.
Above: Near Canyons of the Ancients National Monument, August 9, 2016 and September 1, 2017.
Left: Yellowjacket, Colorado, August 22, 2005.

This very common Sunflower plant grows to 9 feet tall and five feet wide and sports an abundance of large, bright flower heads on many branches.  Leaves are ovate, deltoid, and/or lanceolate and large; flower heads are usually 3-6 inches in diameter. The plant hybridizes and is quite variable, as for instance in the color of the disk corolla which is almost always brown/red/purple (as shown on this page) but can be yellow. The ray floret petal is most commonly yellow/gold (as shown on this page) but can be a bicolored red and yellow.

Helianthus annuus is an annual (thus its specific epithet, "annuus") and is highly successful at reproducing itself from seed.  It is very common along roadsides and in fallow fields. 

"Helios" is Greek for "sun" and "anthos" for "flower".

This new world native species has been, in the words of the authors of Intermountain Flora, "cultivated [in the Americas] since pre-Columbian times for its edible seeds...."  It is now cultivated in many parts of the world.

The genus and species were named by Linnaeus in 1753 from specimens collected in Peru and Mexico.

Helianthus annuus (Common Sunflower)
Asteraceae (Sunflower Family)

Semi-desert, foothills, montane. Disturbed areas, openings. Summer, fall.
Yellowjacket, Colorado, August 22, 2005 and near Canyons of the Ancients National Monument, August 9, 2016 and September 1, 2017.

Flower heads range from three to six inches across and have 100 to 150+ fertile disk flowers with far fewer sterile ray flowers. Commercial varieties have even more fertile disk flowers.

Helianthus annuus (Common Sunflower)
Asteraceae (Sunflower Family)

Semi-desert, foothills, montane. Disturbed areas, openings. Summer, fall.
Canyons of the Ancients National Monument, August 9, 2016 and Yellowjacket, Colorado, August 22, 2005.

The shingled phyllaries of the green involucre are broad ending in a caudate tip (tapering very quickly to a finely drawn out point).

Leaves are typically ovate, deltoid, and/or lanceolate and can grow to an enormous 15 x 15 inches. The largest of those shown are about 5 x 4.

Notice the very stout Helianthus annuus stem in the upper left of the second photograph.

Range map © John Kartesz,
Floristic Synthesis of North America

State Color Key

Species present in state and native
Species present in state and exotic
Species not present in state

County Color Key

Species present and not rare
Species present and rare
Species extirpated (historic)
Species extinct
Species noxious
Species exotic and present
Native species, but adventive in state
Eradicated
Questionable presence

Range map for Helianthus annuus